Abstract: A method for aligning the optical surfaces of the high extraction annular ring resonator which includes a scraper mirror with a decentered aperture. A probe beam, from an external laser, is directed into the resonator cavity through the decentered aperture in the scraper mirror. The symmetrical properties of the probe beam near and far field intensity distribution patterns are used to align the optical surfaces within the cylindrical ring resonator.

Abstract: A device for maintaining a high-energy laser pulse within a recirculating optical delay line for a period time to optimize the interaction of the pulse with an electron beam pulse train comprising closely spaced electron micropulses. The delay line allows a single optical pulse to interact with many of the electron micropulses in a single electron beam macropulse in sequence and for the introduction of additional optical pulses to interact with the micropulses of additional electron beam macropulses.

Abstract: An apparatus for achieving in-phase mode operation of a diode laser. A photonic band gap mirror (photonic crystal) having a periodic lattice structure is placed in front of light emitted from one side of the laser diode array. Because of an incomplete photonic band gap in the photonic crystal, light normal to the crystal will be primarily reflected while light at an angle will be primarily transmitted through the mirror. Since in-phase emission is primarily normal and out-of-phase emission primarily off axis, the reflected light which is directed back into the laser cavity will be the predominant lasing mode. The out-of-phase mode primarily transmitted will have significantly larger losses. The resulting laser diode apparatus will therefore operate in-phase and produce a single lobe far-field distribution.

Abstract: Azimuthal mode control for lasers employs an optical system which rotates the image to produce an optical feedback system, which through interference with the cavity fields, supresses the unwanted modes.